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91.
Akihiko Tanaka Motoaki Kishino Roland Doerffer Helmut Schiller Tomohiko Oishi Tadashi Kubota 《Journal of Oceanography》2004,60(3):519-530
An algorithm is presented to retrieve the concentrations of chlorophyll a, suspended pariclulate matter and yellow substance
from normalized water-leaving radiances of the Ocean Color and Temperature Sensor (OCTS) of the Advanced Earth Observing Satellite
(ADEOS). It is based on a neural network (NN) algorithm, which is used for the rapid inversion of a radiative transfer procedure
with the goal of retrieving not only the concentrations of chlorophyll a but also the two other components that determine the water-leaving radiance spectrum. The NN algorithm was tested using the
NASA's SeaBAM (SeaWiFS Bio-Optical Mini-Workshop) test data set and applied to ADEOS/OCTS data of the Northwest Pacific in
the region off Sanriku, Japan. The root-mean-square error between chlorophyll a concentrations derived from the SeaBAM reflectance data and the chlorophyll a measurements is 0.62. The retrieved chlorophyll a concentrations of the OCTS data were compared with the corresponding distribution obtained by the standard OCTS algorithm.
The concentrations and distribution patterns from both algorithms match for open ocean areas. Since there are no standard
OCTS products available for yellow substance and suspended matter and no in situ measurements available for validation, the result of the retrieval by the NN for these two variables could only be assessed
by a general knowledge of their concentrations and distribution patterns.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
92.
Helmut J. Körner 《Rock Mechanics and Rock Engineering》1976,8(4):225-256
ZusammenfassungReichweite und Geschwindigkeit von Bergstürzen und Flieschneelawinen Die Massenströme großer Bergstürze und Lawinen lassen sich näherungsweise berechnen und abschnittsweise vom Anbruch bis zur Ablagerung nachvollziehen. Die Theorie muß aufgrund der Naturbeobachtung dieser Vorgänge entfaltet werden. Da Bergstürze relativ seltene und schwer zu beobachtende Naturereignisse darstellen, ist es notwendig, Erfahrungen an ähnlichen Massenströmen zu sammeln, wie z. B. an den zahlreichen Fließschneelawinen.Nach Darlegung der Grundlagen an den Modellen Reibungsblock und turbulenter Trümmerstrom werden einige Ergebnisse nachgerechneter Beispiele dargestellt. Ein Ziel dieser Berechnungen war es, die Größenordnungen der Gleitreibungs-und Turbulenzkoeffizienten abzuschätzen, die diese Vorgänge bestimmen. Mangels genauerer Meßdaten wurden dazu die beiden Koeffizienten und die Fließhöhe als Konstanten angesetzt. Dann läßt sich die Größe ihrer Mittelwerte aus dem Bahnverlauf, der Fließdauer (oder der Fließgeschwindigkeit an einem Ort) und aus der Reichweite bestimmen.Es zeigt sich, daß bei großen Massenströmen der Mittelwert des Gleitreibungskoeffizienten wesentlich niedrigere Werte annimmt, als unsere an der Statik orientierte Erfahrung erwarten läßt. Große Gleitmassen kommen dadurch in kurzer Zeit auf hohe Geschwindigkeiten. Man darf deshalb nicht warten bis die Beschleunigung einsetzt, wenn sich das Abgleiten großer Massen durch anhaltendes Kriechen ankündigt und wenn sich kein naheliegender Gleichgewichtszustand nachweisen läßt, dem die Massen zustreben.
Mit 15 Abbildungen 相似文献
SummaryThe Reach and Velocity of Catastrophic Landslides and Flowing Snow Avalanches The debris (Sturzstrom) of catastrophic land-slides and avalanches can be approximately calculated and their stages reconstructed from their outbreaks until their depositions. The theory must be developed on grounds of an observation of these phenomena in nature. As mountain slides are relatively rare natural events and not easily observed, it is necessary to accumulate experiences with similar massstreams, e. g. with the numerous flowing-snow-avalanches.After a representation of the fundamentals, exemplifying the models of a frictional block and a turbulent stream of fragments, some results follow from the calculated examples. One aim of the calculations was to estimate the proportions of the frictional and turbulence coefficients determinating these phenomena. Owing to the lack of exact data of measurement both these coefficients and the height of flow were used as constants. Thus the dimension of their average values can be determined from the shape of course, the flowing time (or local flowing velocity) and the range of action.The results show that in the case of big Sturzstrom the average value of the coefficient of friction grows considerably smaller than is to be expected in the face of our static orientated experiences. As a consequence, big moving masses reach a high velocity within a short time. It is not advisable, therefore, to wait until the acceleration begins, if the sliding down of bigger masses evidences itself by continuous and if it is impossible to prove an imminent stage of equilibrium which the masses are nearing.
RésuméEtendue et vitesse des éboulements d'ampleur catastrophiques et des avalanches en haute montagne Les masses de débris emportés et déposes par les éboulements et avalanches d'ampleur catastrophique en haute montagne peuvent être calculés approximativement, et leur cours peut être suivi depuis leur point de départ jusqu'au lieu de dépôt définitif. La théorie à ce sujet doit être établie sur la base d'observations concrètes de la marche de ces phénomènes dans la nature. Du fait que les éboulements sont des phénomènes relativement rares et difficiles à observer, il importe que soient recueillis des faits d'expérience au sujet d'analogues éboulements de débris, par exemple dans les avalanches, qui sont, elles, beaucoup plus fréquentes.Après exposition des principes, établis sur la base des modèles hypothétiques Bloc de friction et Eboulement de débris en turbulence, sont ensuite présentés quelques résultats de calculs effectués sur la base de ces divers exemples. L'un des objectifs de ces calculs était de déterminer les ordres de grandeur des coefficients de friction et de turbulence de ces phénomènes. Etant donné le manque de mesures précises, ces deux coefficients, ainsi que l'épaisseur de la masse en éboulement, ont été utilisés comme constantes. Il est alors possible de déterminer la grandeur de leur moyenne, d'après le tracé de leur cours, la durée (ou la vitesse de la chute en un point donné), ainsi que d'après leur étendue.Il apparaît alors que, dans le cas de grosses masses de débris, la valeur moyenne du coefficient de friction est nettement moindre que ne le faisait attendre l'expérience jusqu'à présent basée sur les données de la statique. Il s'ensuit que de grosses masses d'éboulis ont tôt fait d'atteindre des vitesses étonnamment élevées. Il ne faut donc pas attendre que commence cette accélération lorsque l'éboulement de grosses masses s'annonce par un mouvement lent et continu et qu'on ne décèle dans le voisinage aucun état d'équilibre vers lequel s'avanceraient les masses.
Mit 15 Abbildungen 相似文献
93.
Tamara T. Helfer Michael W. Regan Michele D. Thornley Tony Wong Kartik Sheth Stuart N. Vogel Douglas C.-J. Bock LEO Blitz Andy Harris 《Astrophysics and Space Science》2001,276(2-4):1131-1139
BIMA SONG is a systematic imaging study of the 3 mm CO J = 1 → 0molecular emission within the centres and discs of 44 nearby spiral galaxies on size scales of a few hundred parsecs
(6-9"). The overall goal of the survey is to study the role of molecular gas in the evolution of spiral galaxies. To this
end, BIMA SONG addresses 1) the distribution and physical conditions of the molecular gas in galactic discs and its relation
to star formation, 2) the effects of a stellar bar on the kinematics of molecular gas, including the possible inflow of gas
along a bar, and 3) the distribution and role of molecular gas in the central few hundred parsecs of active and quiescent
galaxies. The source list includes all (except M33and M31) 44 galaxies of Hubble types Sa–Sd, with declinations δ >−20°, visual magnitudes B < 11.0, velocities v
hel <2000 km s-1, and inclinations i < 70°. Beyond the specific scientific questions we will address, this survey will provide a unique database for astronomers who
study galaxies at all wavelengths.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
94.
Inhalt Optische und röntgenographische Untersuchungen zeigen, daß die Quarzstengel im Schriftgranit von Zwiesel über mehrere Zentimeter in ihrem optischen Drehvermögen und in der Orientierung konstant bleiben.Mit 1 Textabbildung 相似文献
95.
Application of210Pb in soils 总被引:2,自引:0,他引:2
Helmut Dörr 《Journal of Paleolimnology》1995,13(2):157-168
The spectroscopic measurement of soil samples is described.210Pb data from a soil survey in western-Europe are briefly reviewed. The average210Pb flux from the atmosphere, as determined from210Pb
exc
soil inventories, is 90 Bq m–2a–1. A simple one-dimensional box-chain model is described. The model simulates the vertical, post depositional transport of natural and fall-out radionuclides in the soil. Simulation of measured210Pb
exc
,134Cs,137Cs, and241Am soil profiles shows that mixing (bioturbation) is a very efficient transport mechanism. Lead seems to be strongly fixed to organic and clay particles. It is transported by the displacement of the organic and clay carrier substances. The mean residence time of lead, caesium, plutonium and americium in organic rich forest soils is in the order of 250–1000 years. An applicability study in investigate the use of210Pb in erosion problems showed erosion rates from 60–180 g m–2a–1 on organic rich forest and meadow sites with 10°–25° slopes.This is the eighth of a series of papers to be published by this journal following the 20
th
anniversary of the first application of210Pb dating of lake sediments. Dr P. G. Appleby is guest editing this series. 相似文献
96.
T. Dunkel E. L. de León Gallegos C. Bock A. Lange D. Hoffmann J. Boenigk M. Denecke 《International Journal of Environmental Science and Technology》2018,15(6):1139-1158
In this study, Illumina sequencing was used for the identification of bulking and foaming bacteria in industrial wastewater treatment plants. The reliable identification of bulking and foaming bacteria represents the first step in developing effective and specific control strategies to avoid disturbances in activated sludge systems. Illumina sequencing revealed 432 16S rRNA operational taxonomic units, representing phylotypes and including 21 bulking and foaming bacteria in the two investigated industrial wastewater treatment plants. Foaming represents the most severe problem in the cascade biology system. Up to 22.5% of all sequencing reads are bulking and foaming bacteria, including Chryseobacterium, Candidatus Microthrix parvicella and Gordonia sp. as the dominant bulking and foaming bacteria which are known for foam formation. Moreover, Illumina sequencing revealed an increase in Candidatus Microthrix parvicella and Gordonia sp. reads from activated sludge to foam and scum samples, indicating a preferred flotation and/or growth advantages in the foam and scum layers. Analyses of the taxonomic assignment and distribution showed that the phylum Actinobacteria is the most dominant phylum, underlining the key role of Actinobacteria in bulking and foaming. Multivariate data analysis was applied, revealing that the dominant bulking and foaming bacteria are positively correlated with the sludge age and influent flow and negatively correlated with the dissolved oxygen level and the temperature. In terms of developing a specific control strategy, the positive linear relationships to the fatty acid and surfactant sludge loadings are highlighted and the removal of lipid compounds from the wastewater influent could avoid an overgrowth of bulking and foaming bacteria. 相似文献
97.
Kristof Plankensteiner Bernd M. Rode Tomas Mikoviny Armin Hansel Georg Fischer Helmut O. Rucker 《Icarus》2007,187(2):616-619
Saturn's moon Titan has been considered as one of the few places in our Solar System, where atmospheric and surface conditions could have produced organic compounds essential as precursors for an evolution of life. The Cassini-Huygens mission has provided new data on Titan's atmosphere and surface, which enabled us to simulate the chemical processes occurring under these conditions. Possible lightning events on Titan cannot only produce higher hydrocarbons, but also allow surface water ice to participate in the reaction scenario, resulting in CHO, CHN, and CHON compounds including several molecules relevant for the formation of amino acids and nucleic acids. 相似文献
98.
Helmut Tenzer Chan-Hee Park Olaf Kolditz Christopher Ian McDermott 《Environmental Earth Sciences》2010,61(4):853-880
Earth-reservoirs are increasingly exploited today with the extraction of resources, such as heat and hydrocarbons, and the
large-scale emplacement of waste, such as CO2 sequestration. The characterization, site investigation, predictive modeling and long-term monitoring are dependent on the
processes being investigated and modeled. In most cases complex coupled processes have to be addressed in a geologically complex
rock mass system. In this paper we present a conceptual holistic framework known as geomechanical facies linking all the scales
of investigation, characterization and reservoir development methods. We demonstrate this concept on the work undertaken during
the design and development of the enhanced geothermal systems (EGS) systems at the forefront of European Hot-Dry-Rock (HDR)
technology, Soultz-sous-Forêts (France) and Spa Urach (Germany). Soultz-sous-Forêts is situated within granitic rocks and
an active tectonic graben system in the central part of the Rhine Graben. It presents conditions of lithology, temperature,
stress, hydraulics and geochemistry that are very different from those at Spa Urach, located in a very dense gneiss formation
in the South German crystalline complex. Spa Urach exhibits more elastic behavior and is set tectonically within an almost
inactive strike-slip stress field described in more detail in Sects. “Drill core analysis” and “Hydraulic stimulation at Spa Urach”. This paper compares the exploration and field development methods used at these two sites against the back drop of the
geomechanical facies concept. Issues addressed include the key parameters for flow and heat transport properties, coupled
hydro-mechanical process identification, the success of the HDR reservoir as a heat exchanger and exploration techniques applicable
to the different facies. Identification of the key geomechanical facies gives an indication as to which technologies will
prove more efficient in the application of HDR technology. The results of this study will hopefully help in developing heat
recovery schemes for the long-term economical operation of future HDR plants and EGS as well as assist in the understanding
of engineered geosystems. 相似文献
99.
100.
Dr. Achim Hirschberg Helmut G. F. Winkler 《Contributions to Mineralogy and Petrology》1968,18(1):17-42
The stability relations between cordierite and almandite in rocks, having a composition of CaO poor argillaceous rocks, were experimentally investigated. The starting material consisted of a mixture of chlorite, muscovite, and quartz. Systems with widely varying Fe2+/Fe2++Mg ratios were investigated by using two different chlorites, thuringite or ripidolite, in the starting mixture. Cordierite is formed according to the following reaction: $${\text{Chlorite + muscovite + quartz}} \rightleftharpoons {\text{cordierite + biotite + Al}}_{\text{2}} {\text{SiO}}_{\text{5}} + {\text{H}}_{\text{2}} {\text{O}}$$ . At low pressures this reaction characterizes the facies boundary between the albite-epidotehornfels facies and the hornblende-hornfels facies, at medium pressures the beginning of the cordierite-amphibolite facies. Experiments were carried out reversibly and gave the following equilibrium data: 505±10°C at 500 bars H2O pressure, 513±10°C at 1000 bars H2O pressure, 527±10°C at 2000 bars H2O pressure, and 557±10°C at 4000 bars H2O pressure. These equilibrium data are valid for the Fe-rich starting material, using thuringite as the chlorite, as well as for the Mg-rich starting mixture with ripidolite. At 6000 bars the equilibrium temperature for the Mg-rich mixture is 587±10°C. In the Fe-rich mixture almandite was formed instead of cordierite at 6000 bars. The following reaction was observed: $${\text{Thuringite + muscovite + quartz}} \rightleftharpoons {\text{almandite + biotite + Al}}_{\text{2}} {\text{SiO}}_{\text{5}} {\text{ + H}}_{\text{2}} {\text{O}}$$ . Experiments with the Fe-rich mixture, containing Fe2+/Fe2++Mg in the ratio 8∶10, yielded three stability fields in a P,T-diagram (Fig.1):
- Above 600°C/5.25 kb and 700°C/6.5 kb almandite+biotite+Al2SiO5 coexist stably, cordierite being unstable.
- The field, in which almandite, biotite and Al2SiO5 are stable together with cordierite, is restricted by two curves, passing through the following points:
- 625°C/5.5 kb and 700°C/6.5 kb,
- 625°C/5.5 kb and 700°C/4.0 kb.
- At conditions below curves 1 and 2b, cordierite, biotite, and Al2SiO5 are formed, but no garnet.